Adults born preterm with very low birth weights may face increased risk for metabolic syndrome, according to findings published in The Journal of Clinical Endocrinology & Metabolism.
“Low birth weight and prematurity have emerged as risk factors for metabolic syndrome,” Chandima Balasuriya, MD, of the department of clinical and molecular medicine at Norwegian University of Science and Technology, and colleagues wrote in the study background. “Globally, around 15 million preterm births occur annually. ... A substantial number is also born small for gestational age at term. Most studies have addressed metabolic profile in individuals with low birth weight born premature or without specified gestational age. Adults born very preterm or at very low birth weight have been reported to exhibit higher blood pressure than term-born adults with normal weight.”
In a follow-up study, Balasuriya and colleagues analyzed data from two cohorts of white adults born between 1986 and 1988, including 55 adults born preterm with very low birth weights (< 37 weeks and weighing 1,500 g), 59 adults born at full term but small for gestational age ( 37 weeks; birth weight in the 10th percentile or lower) and 75 adult healthy controls.
The study’s primary outcomes were measures of metabolic syndrome: waist circumference, BP, HDL cholesterol, triglycerides and fasting blood glucose. Participants completed a questionnaire pertaining to smoking status, physical activity, medical conditions and medications. The researchers also measured participants’ body weight, height, waist circumference and hip circumference to calculate BMI and waist-to-hip ratio.
The researchers defined metabolic syndrome as having any three of the following: central obesity (waist circumference ≥ 94 cm in men and 80 cm in women); triglycerides at least 1.7 mmol/mL; HDL cholesterol less than 1.03 mmol/L in men and less than 1.29 mmol/L in women; being on treatment for high BP or hypertension; fasting plasma glucose of 5.6 mmol/L; and previously diagnosed type 2 diabetes or being treated for diabetes.
The researchers found that the groups had similar waist circumference and waist-to-hip ratio. In an analysis adjusted for adult weight, height and physical activity, term-born adults born small for gestational age had higher waist circumference vs. controls (mean, 85.79 cm vs. 83.99 cm; P = .02).
Men had higher overall systolic BP (mean, 127 mm Hg vs. 117 mm Hg; P < .001) and diastolic BP (71 mm Hg; P = .06) vs. women. Compared with control women, women born with very low birth weight had higher systolic BP, whereas men born with very low birth weight had comparable BP with control men. Adults with very low birth weight had higher mean arterial pressure and mean heart rate. The differences in BP and mean arterial pressure persisted after adjusting for confounders, according to researchers. Adults born with very low birth weight also had higher HbA1c and C-peptide levels vs. controls, as well as greater insulin sensitivity.
Men born with very low birth weight had higher fasting glucose (mean, 5.1 mmol/L vs. 4.98 mmol/L) and HbA1c (mean, 5.3% vs. 5.05%) vs. men in the control group.
Within the cohort, 9.5% had metabolic syndrome, and it was more prominent in men vs. women. Adults born with very low birth weight had higher prevalence of metabolic syndrome (13%) vs. controls (7%), as did adults born at full term but small for gestational age (10%), although this difference did not reach significance. A higher proportion of adults born with very low birth weights had at least one characteristic of metabolic syndrome vs. controls (72% vs. 55%; P = .048) Women born with very low birth weight had higher metabolic syndrome scores vs. control women and women born at full term but small for gestational age. There were no between-group differences for men for metabolic syndrome scores, according to researchers.
In men, researchers also observed a positive correlation between metabolic syndrome score and spine and whole-body bone mineral density, as well as a negative correlation between metabolic syndrome score and trabecular bone score. Researchers observed similar correlations when analyzing individual metabolic syndrome components apart from HDL cholesterol, which correlated inversely with BMD and positively with trabecular bone score.
“Both low birth weight groups, and particularly the [very low birth weight] females, displayed a more unfavorable metabolic profile than did controls,” the researchers wrote. “[Term-born, small for gestational age] individuals seemed to be at increased risk, although the majority may be constitutionally small. The inferior bone quality in those with high metabolic syndrome score may imply increased future fracture risk.” – by Jennifer Byrne
Disclosures: The authors report no relevant financial disclosures.